Elevator control system



April v18, 1944. s, T. HUNT 2,347,054

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/ce v I 9. /De Ppe I GMP3 C3 wlTNEssEs; A INVENTOR fdwyg; Fig: /4/7.5MM@ T//mvf I ATTONEY Patented Apr. 18, 1944 ELEVATOR CONTROL SYSTEMStanley T. Hunt, Northampton, England, assigner to Express Lift CompanyLimited, London, England, a British company Application May 13, 1942,Serial No. 442,869 In Great Britain June 13, 1941 (C1. IS7-29) 13Claims.

My invention relates to electrical controlling systems for cars and,more particularly, to means for controlling the starting and stopping ofa plurality of interconnected elevator cars.

It is the object of the present invention to provide means forautomatically distributing landing calls to two or more cars so that thedisparity in waiting times, whereby some of the prospective passengersare required to wait for a short period and others for a long period, isconsiderably reduced.

According to a feature of my invention, in an electrical car systemhaving a plurality of interconnected cars, the cars are preferablyequally spaced over their full distance of travel. By representing thefull distance of travel as a circular track, and in a system havingthree cars, the cars would be spaced 120 degrees apart. A car so spacedwith relation to the preceding car is said to be in the desiredposition. A car which, owing to traffic conditions, becomes positionedso that it is spaced, say, 160 degrees from the preceding car, is saidto be in the rst delayed position. A car which becomes spaced more than,say 210 degrees from the preceding car is said to be in the seconddelayed position. Means are provided whereby the above mentionedarbitrary spacings between a ycar and the preceding car areautomatically adjusted according to the number of cars in service andthe traiiic conditions.

According to another feature of my invention, l provide means forrecording the periods of time for which every unanswered landing callhas been accepted. The aforesaid periods of time are classified underthree headings viz: short term, medium term and long term calls. Theperiod of time represented by each of the three Classif.- cations may,for example, be such that the expression short term includes calls whichhave been accepted for a period not longer than l seconds, medium termincludes calls which have been accepted for between and 25 seconds, andlong term includes all calls which have been accepted for a period ofmore than 25 seconds. The periods of time may be arranged to suitcharacteristics of a particular elevator installation and may beautomatically adjusted according to varying traffic conditions and/ orthe numw ber of cars in service at any time.

According to a further feature of my invention, I provide means forrecording the number of unanswered landing calls which has been acceptedby any car. A car having accepted at least, say, three unansweredlanding calls is said to have its half quota. A car having accepted morethan,

say, six landing calls is said to have its quota and a car havingaccepted more than, say twelve landing calls is said to have its excessquota.

The number of calls included in each of the above three classicationscan be varied to suit prevailing traic conditions and/or the number ofcars in service at any time.

(a) A car in its desired position will accept all landing calls withinits zone (i. e. short term, medium term and long term calls).

(b) A car in a rst delayed position and having its half quota of calls,will refuse all short term calls, and will accept medium term and longterm calls.

(c) A car in'a second delayed position and having its half quota ofcalls will refuse short term and medium term calls, and will accept longterm calls.

(d) A car having its quota of calls will refuse short term calls, andwill accept medium term and long term calls.

(e) A car having an excess quota of calls will refuse short term andmedium term calls, and will accept long term calls.

The following further features are incorporated in my invention:

(f) An illuminated signal or the like is provided at the principal orparking oor (usually the ground licor) above the entrance to each car.The said signal is illuminated upon the arrival of its associated car,provided that no other car is waiting at that oor. If more than one cai1arrives at the parking oor, only the signal associated with the firstcar to arrive will be illuminated. Upon departure of the first car, thesignal associated with the second car will be illuminated.

(g) When no car is standing at the parking floor, the car in the zone inwhich the parking floor is situated at the appointed time, will travelto the parking iioor when all its landing calls have been answered.

(h) When the car to which a call has been assigned, fails to start or,after starting, comes to rest for a period of time in excess of aDredetermined period, the landing calls which the lift car has acceptedbut not answered, are transferred to other cars according to thepositions oi the latter in relation to the calls.

(i) Although the system may be fully automatic, it is understood that,in accordance with general practice in elevator systems of this type,each car may be placed under the control of an attendant. The attendant,however, merely starts the car by operating a starting handle or thelike in response to a signal which indicates that a call exists Withinthe operating zone of his car. The system otherwise operatesautomatically according to the manner already described.

When a car is under the initial control of an attendant, a by-passbutton is provided by means of which unnecessary delays due to a fullyloaded car stopping in response to landing calls are prevented. Theby-pass button -is momentarily operated by the attendant when the car isfully loaded, whereupon the car will not stop to answer any landingcalls until after it has stopped to deliver a passenger. The car willthen revert to the normal method of operation which existed before theby-pass button .was operated. A.It (is,

therefore, not necessary for the attendant vto maintain the by-passbutton switchoperated and the diiiiculty which would arise'if Aalockingtype of switch were used viz.: that of inadvertently allowing the switchto remain inthe .bypass position, is avoided.

In an Varrangement Yaccording 'to 'one embodiment of my invention, ,upand downlanding calls are accepted on a controlling device, which iscommon to all cars, and are distributed `to the cars according to thekfloor from whi-ch a call is originated, the direction in which thecaller intends `to travel, the positions of thecars, andthe direction inwhichthey are travelling.

To facilitate the even distribution or landing A calls, up and downregistering mechanisms are provided at each iloor'to recordtheacceptance of a cal1 andfto classify the call according to the lengthof time the call has beenaccepted. For this purpose, an impulseproducing mechanisin, common to all the cars, periodically steps theappropriate registering mechanism on .iloors from which calls have beenaccepted. Depending, therefore, upon the number ofsteps taken by theregisteringmechanism, acall is ,classied and assigned to a car.Theperiodof time lelapsing between lthe periodic stepping of theregistering mechanism by the impulse producing mechanism is dependentupon the numberfof cars in service and the number of cars in excess of apredetermined number which are ina rst or second delayed position and/orvhave .an excess quota of unanswered calls. n

In order that the nature of my said invention may be more completelydescribed and ascertained, reference should now be made to theaccompanying drawings in which the Figures l1 to 16 are circuit diagrams`for a three 'car elevator systemserving ten floors, ,andthe Figures 1Ato 16A are key diagrams of Figs. 1 to16.

VIn reading the drawings, the key'sheets should be placed vat the rightof the wiring circuits, when 'it will be found that the coils of therelays and their contacts are in horizontal alinement in both sets ofdrawings. The carsare designated X, Y and Z. The relays individual `tothe cars are shown for car X. The corresponding 'rela-ys ffor cars Y andZ `are given the same --designationplus the letter Yor ZV-as the casemay be.

The functions of the relays and vtheir designations are as follows:

IC to ISC (Fig. 1) `Gar call Nstorage relays.

2U to yISU (Fig. ,2), Up landing call `,storage relays.

ID to 9D (Fig. 2), Down landing call storage relays.

IF to IDF (Fig. 3),F1oor selector relays.

lI Gto IDG (Fig. 5) Floor position relays.

vI'I-I to IilH (Fig.3), Upfzone relays.

IK to IIJK (Fig. 5), Down zone relays.

A (Fig. 8) ,Lift running relay.

UP (Fig. 8), Up contacter.

DN (Fig. 8) Down contactor.

AU (Fig. 6), Up direction relay.

AD (Fig. 6) Down direction relay.

BU (Fig. 7), Initial up direction relay for landing calls.

BD (Fig. '7 ,Initial down :direction lrelay for landing calls.

G (Fig. 8), Lift gate relay.

UD (Fig. 8) Auxiliary to AU and AD.

-US (Fig.8) Up terminal limit relay. .DS (Fig. `8), .Down terminal limitrelay. PP (Fig. 16) Pass relay.

TS (Fig. 8),.-Stopping time interval relay. TF (Fig. 8), Startingfailure relay.

;MA (F ig;,8) Out of service relay. 'S '(Fig.'3) "Stationary contacts onfloor selector.

SL-(Fig.l-l), Slow down relay.

SR (Fig. 8) Stopping inductor contacts.

TK (Fig. 12) Landing call pulse Itiming relay.

'i X (Fig. 13) ,Pulse timing cut-off relay.

TY (Fig. 13), Pulse timeregulating relay.

ST (Fig. 9),"First-delayed position relay.

MT (Fig. 9), Second-delayed position relay.

-HQ- (Fig. 10), Half-quota relay.

FQ (Fig. 10) Full quota relay.

EQ (Fig. 10), Excessquotamrelay -SQ (Fig. l1) Short'term call relay.

MQ (Fig. 11) Medium term callrelay.

U2 to U9 (Fig. 15), Driving magnets of up landing calltimingswitches.

D2 t0 D9 (Fig. 15), Driving magnets fof down landing call time switches.

lin Figure l isshown the car call storagerelay group, one such group.being associatedwithieach of `the three cars. `.One storage-relayisprovided for eachfof the ten :floors When the istop hutton in the carfor floor (i is operated, the corresponding car call storingzrelayECoperates to store or register the call. Therelay is released byenergizing its -secondwinding when .the car stops at iioorf, vthe.connection -toxthe two Windings of the relay -beingsuch vthatcurrentjflows .in opposite directions.

A lamp NL which, when illuminated, indicates that the car is `the nextone to leave, vis fitted above the entrance to each car at floor 1. Thelamp is employed in connection with a feature whereby, when a car havingfloor `I .iinf'its-zone, has no further calls, it is parked at thatfloor. This feature is explained in connection with Figure 2 laterinthis specication. As described in connection with the vzone relays-'(Figs. 3 and 5) later in the specification, up zone relay IH operateswhen floor I is iinthe'zoneof the car, and the relay can only beoperated for A'one carat a time. When the car reaches lfloor I,carrunning relays Aand floor position relay IG are unoperated and upzone relay II-I'is operated, provided no 'other car-is already at thatfloor, andits next to leave Vlainp NL is illuminated.

In l.Figure 2 is shown the lhall landing call storage relay groupWhich'is common .to all three cars. On each of the floors v2 to 9 vareprovided up and down push buttons. IOnly .onepus'h button is provided atthe bottom landingat oor I and at the top landing atiloor I0 for obviousreasons. The ,top landing button is calledan up button because the carsmust go up to answer it, while the bottom button is called a down buttonbecause the .cars must `go down to answer it. A call storage relayisassociated with each iioor push button. A prospective passenger at floor3 wishing to travel up, operates the up landing push button 3 whereuponrelay 3U operates, whilst a prospective passenger at floor 6 wishing totravel down, operates the down landing push button 6 to operate relay6D. A landing call relay is released when a car stops at the appropriateoor from the corresponding direction, the second winding of the relaybeing energized to neutralize the magnetic ux created by the firstwinding.

The operation of a landing call storage relay originates circuitoperations for bringing a car to the corresponding oor.

When a car having floor I in its zone has no further calls, contactsBU4, BD4 and IHIB (explained later in this specication) complete acircuit for the down landing call storage relay ID which causes the carto travel to floor I and park in that position until it is required toanswer further calls in its zone.

In Figs. 3 and 5 the floor selector relays IF to IIJF are controlled bymeans of the contacts SI to S9 on a floor selector arranged to beactuated as the car travels between the various oors. The oor positionrelays IG to IIJG are controlled by the contacts of the floor selectorrelays IF to IIlF. The periods during which contacts SI to SB areopened, relays IF to I 0F are released, and relays IG to IUG areoperated according to the position of a car, are shown in Fig. 4.

In the particular embodiment of my invention shown in the drawings, thecars answer calls in their respective operating zones according to thecircular track principle.

The operating zone of a car is indicated by means of the up and downzone relays IH to IDH and IK to IGK respectively; the relays for aparticular car being interconnected with contacts of similar relays onall three cars, If a car is travelling in an upward direction, it willhave operated the H relay corresponding to the floor at which it ispositioned and the H relays corresponding to all oors between itselfandthe car ahead traveling in the same direction. If the car immediatelyahead of it, according to the circular track principle, is travelling inthe down direction, the up-zone H relays corresponding to all floorsabove the car will be operated, together with the down relays in the IKto IDK group corresonding to all fioors above the car ahead, thus thezone extends up to the upper terminal and down to the car ahead.

Similarly, a car travelling in the down direction will have its downzone relays K operated corresponding to the floors between it and thenext car ahead of it. If the latter car is travelling in the updirection, the first car will have all its down K relays operatedcorresponding to all the floors below it, together with the up H relayscorresponding to all floors below the car ahead; that is, the zone willextend down to the lower terminal and up to the nearest up car.

When a car leaves a oor, the corresponding H or K zone relay for thatcar will release and will operate in the equipment of the car in thefollowing zone.

If a car reverses its direction of travel so that it becomes positionedbehind la different car to that which it has previously been positioned,the H and K zone relays of al1 cars are corrected to correspond to therevised positions of the cars.

When two cars become similarly positioned while both are travelling inthe same direction,

on to relay IK.

the H or K zone relay will remain operated for the first car 'to arriveat that position, the relay associated with the second car not operatinguntil the rst named car is ahead of it. If, however, the second carovertakes the :first car, the H or K zone relay for the second car willoperate and the equivalent relay for the rst car will release.

Assuming that car X is at oor 2 travelling in an upward direction,auxiliary relay UD will be operated because a call has been receivedfrom a floor above the position of the car. Floor selector relays IF'and 3F to IBF will be operated (relay 2F is not operated becausecontacts SI and S2 are open). Assuming also that cars Y and Z are out ofservice, a circuit is completed for the upper winding of up zone relay2H from positive, operated MAA and TF3 (the operation of these relays isdealt with later), upper winding of relay 2H, normal 2H3(Y), EHMZ), 2F1and operated UD4 to negative. Operated 2H2 completes a similar circuitfor relay SH2 then completes a circuit for relay El and so on up torelay IUI-I.

Operated IUHII and I BH2 now complete a circuit for relay IGK; IKEoperates relay .9K and so IKZ operates relay IH.

Car K has, therefore, an operating Zone extending over the ul1 circulartrack.

II? car Y is brought into service at a ioor above that at which car X ispositioned (floor 2), and if car Y travels upwards, a circuit will becompleted for its up zone H relay corresponding to the floor at which itis positioned and the operation of the relay will open the circuit ofthe corresponding zone relay for car X, the latter relay then releasingthe H and K relays corresponding to the floors beyond car Y. Zone relaysfor car Y equivalent to those released :for car X will be operated, thecircuit operation being as described for car X.

If car Z is brought into service and is travelling downwards at floor 5,its down zone relay 5K will operate and release relays 5K to I K andrelay IH for car X, the equivalent relays operating for car Z.

When a car leaves a loor, the circuit of the lower winding of thecorresponding H or K zone relay is closed. This winding is connected inopposition to the upper winding and the relay releases. If, for example,car X moves upwards from the second floor, oor selector' relay 3Freleases. Since relay ZF is also released, normal contacts SF and 2F5energize the lower Winding of relay 2H via operated UDS. When relay 2Hreleases, contacts ZHZ open one circuit of relay but a hold circuit ismaintained by normal 3PT.

Normal EHMX) for the car Z equipment opcrates relay 2H for car Z andfloor 2 is consequently transferred from the zone of. car X to that ofcar Z.

As already mentioned, if a car reverses its direction of travel, all thedoors between its position and the car previously ahead of it arereleased and are operated for the car which was behind it. lr", forexample, car Y which is at door 8 reverses to travel downwards,auxiliary relay UD releases. The negative feed to all the H up zonerelays is opened at UDII and a circuit is closed for the K down zonerelays at normal UDE. On car Y, zone relays 8H, SH, 10H, IGK and 53Krelease, the circuit of up zone relay 8H being maintained by normal #BFEfl.

The release of relay for car Y allows SHSVY) to operate relay EH for carX, the latter relay then operating up zone relay 9H. The zone relays iH,ItK and 9K also operate for car X.

In Fig. 4, as stated above, is shown the periods during which selectorcontacts SI to S9 are opened, floor selector relays IF to IGF arereleased and floor position relays IG to IIiG are operated.

In Fig. 7, initial direction landing call relays BU and BD operateaccording to whether a landing cali is above or below the position ofthe car. If a call is registered at a position above the car, relay BUoperates. If a call is registered at a position below the car, relay BDoperates.

As already explained, the operating zone of a car is indicated by theoperation of the Zone relays in the Ii-I to IIlI-i and IK to IK group.Contacts in the groups ZI-II to ISI-II and IKI to QKI are accordinglyoperated in the circuits of relays BU and BD. All the contacts in theIFS to IIlFS group will be operated with the exception of the contactsof the relay corresponding to the position of the car, therefore, thecontacts of all landing call relays ID to SD and 2U to ISU, and contactsof the zone relays IH to IIlI-I and IK to Ill above the point at which acontact in the IFS to IF group is opened, will operate relay BU and allcontacts below that point will operate relay BD.

If calls exist above and below the car, and such calls are in the zoneof the car, both BU and BD will operate.

Relays US and DS are released at the upper and lower terminal noors,respectively, by contacts ULI andr DLI of the up and down limitswitches.

In Figs. 7 and 8, relays AU and AD are operated firstly under thecontrol of car calls above or below the car respectively, in a mannersimilar to that already described for the operation of relays BU and BD.Contacts IC2 to I 8C2 of the car call storage relays close a positivefeed to the contact chain comprising contacts IFI to I IJFI. ContactsADB and AUS, in the negative feeds to relays AU and AD respectively,ensure that only one of the relays can be operated at the same time.Secondly, relays AU and IAD are also controlled with regard to landingcalls by BUI and BDI. Once operated, relays AU and AD hold via AU2 andTSI and AD2 and TS2, respectively, the contacts of relays TS remainingclosed for a predetermined period of time after the car has come to restat a oor.

Contacts AUII control the up contacter UP, and ADA control the downcontactor DN. The contactor relays UP and DN operate the usual controlsystem of the car to cause it to run up or down and inasmuch as controlsystems are old and well known, no further description will be given. Itwill be seen, therefore, that the operation of relay AU or AD causes thecar to move up or down to answer landing calls within the operating zoneof the car, and also to deliver car call passengers.

topping time interval relay TS is operated by contact A3 of lift-runningrelay A. which indicates that the car is running and is controlled bycontacts UPE and DN?. Relay TS remains operated for a predeterminedperiod after its circuit is opened by A3.

Relay TF is the starting failure relay which is operated when thebattery supply is switched on. Operated TFI provides a holding circuitin series with normal contacts BU2 and BDZ.

When the car is scheduled to start in response to landing calls, relayBU and BD operate whereupon BU or BD? open the circuit of relay TF (MABis open at this time as explained later). If the car moves, relay Aoperates and A4 holds fil relay TF. If, however, the car fails to move,relay A will not operate and relay TF will release at the end of itspredetermined release period. Contacts TF3 and TF4 release relays IH toIGH and IK to IIIK, consequently the car loses its operating zone whichis transferred to the following car.

The starting failure relay TF remains released until one of the othercars commences to slow down. Contacts SLI of slow down relay SL on theother car then reoperates relay TF.

Out of service relay MA, which operates when the service switch SS isclosed and relay 'TF is operated, remains held via MAII. When it isnecessary to withdraw the car from service for maintenance or otherpurpose, the service switch is opened and relay MA releases. ContactsMAG and MAE open the circuits of relays IH to IDH and IK to IK, therebytransferring the zone of the car to the following car.

Auxiliary relay UD operates via AU and normal ADS when the car isoperating in an upward direction. Operated UD2 provides a hold circuitfor the relay until ADE opens when theY car is required to traveldownwards. Contacts of the auxiliary relay UD control zone relays IH toIH and IK to IGK as explained earlier in the specification under thedescription of Figs. .'-l and 5.

In Figs. 9, 10 and ll, relays ST and MT operate accordinCr to whetherthe car is in the rst delayed or second delayed position.

In a ten-floor elevator installation, the total number of up and downzone relays for the full car travel is 18. When referring, therefore, toa three car system in which the distances between the cars aresubstantially equal (i. e. in which the operating Zones of all cars areequal), a car referred to as being in the desired pesition would have 6or 7 zone relays operated.

As a car Zone becomes extended owing to traiicconditions, the number ofits zone relays oper.

ated will increase. When the number of operated zone relays exceeds adesired predetermined number, the car is said to be in the irst delayedposition and the first delayed relay ST operates. If the car becomesfurther delayed so that the number of operated Zone relays exceed agreater predetermined number, the car is said to be in the seconddelayed position and the second delayed relay MT operates.

The current flowing through relays ST and MT is proportional to thenumber of IK to IK5 and IH5 to IIIH5 zone relay contacts operated, allthe resistances RA to RU being of equal value. Hence when a selectedpredetermined number of zone relays for a car are operated, sufficientcurrent flows through the resistances connected in parallel by theoperated zone relayv contacts to operate the relay ST and condition thecircuits in accordance with the first delayed position of that car.Similarly, when a greater predetermined number of zone relays for a carare operated, sulcient current flows through thev second delayed relayMT to operate it to condition the circuits in accordance with the seconddelayed position of that car. The resistances RY and RZ provide means bywhich the relays ST and MT may be readily adjusted for the desiredaction.

The half quota relay HQ, the full quota relay FQ and the excess quotarelay EQ are controlled in a Similar manner to relays ST and MT, but inthis case contacts EU8 and/or 2D8,

etc. of the landing call relays are connected in'vv

